A structural inspection undertaken during 2015 identified a crack in the caisson wall at spider deck level. A temporary fall arrestor was installed and a replacement caisson was required.
Scope & Deliverables
The engineering scope was based on a BOD supplied by the client. The scope comprised engineering and design of a new caisson supported at the cellar deck level. Design included lifting associated with removing the existing caisson and installing the new caisson.
Deliverables consisted of 2D/3D CAD drawings and construction work packs. An animation was produced to assist during the HAZID forum and construction phase.
Fully welded dead weight support at cellar deck to be removed and replaced. Caisson removed using traditional pin and cut method. Caisson installed using the platform crane in 12m sections and welded inside habitat. Hand held 3D scanner was used to survey caisson corridor to establish destruct requirements prior to caisson installation.
Caisson was planned to be replaced during the summer of 2016 which meant the duration to complete the site survey, destruct and construct workpacks was fast tracked and delivered in 8 weeks. Caisson tubular sections were ordered prior to SCE appointment. SCE prioritised fatigue assessment on resulting weld elevations and corresponding wave loading data.